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Re: duplicate values for primary keys
Posted by: Rick James
Date: July 12, 2010 11:49PM

primary key (username, email_addr)
-->
primary key (username),
unique (email_addr)

The first says that the _combination_ is never to be repeated. The other says that _each_ must never be repeated.

Note: PRIMARY KEY implies UNIQUE.

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Subject
Written By
Posted
duplicate values for primary keys
Chris Bassett
June 29, 2010 11:49PM
Re: duplicate values for primary keys
Rick James
July 01, 2010 11:17PM
Re: duplicate values for primary keys
Chris Bassett
July 11, 2010 09:27AM
Re: duplicate values for primary keys
Rick James
July 12, 2010 11:49PM
Re: duplicate values for primary keys
Chris Bassett
July 12, 2010 11:58PM


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